Repo move: restore hosted gh-aw E2E and migrate the gh-aw package identity to github/squad/workflows #2403

After the move to github/squad:

• Hosted E2E skipped: squad-gh-aw-hosted-e2e.yml is guarded by github.repository == 'bradygaster/squad', so the hosted E2E is skipped without any error.
• Package name hardcoded: workflows/shared/squad-install-verifier.mjs hardcodes and enforces the gh-aw package name bradygaster/squad/workflows. A consumer who installs github/squad/workflows@<sha> fails --verify-install.
• Action reference: Actions doesn't follow repository redirects for uses:, so uses: bradygaster/squad/.github/actions/squad-init@<sha> should name the new owner. The action's default release repository is also still bradygaster/squad.
• Dead docs link: the gh-aw-enlistment skill links the docs guide on the old host, which now returns 404.

Fix

• Key the E2E guard on the repository ID.
• Make github/squad/workflows the canonical name, while existing bradygaster/squad/workflows installs keep verifying.
• Document the upgrade path, and which revisions support the new name.